A lens actuator is calibrated by inputting a signal to the actuator to cause the actuator to move a lens from a first location to a second location, sensing a focus error signal generated in response to the movement of the lens, determining a distance moved by the lens in going from the first location to the second location from a predetermined characteristic of the focus error signal, and determining a gain of the actuator from the input signal and the distance moved.
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1. A method of calibrating a lens actuator, comprising:
inputting an oscillating signal into the actuator, causing the actuator to oscillate a lens, wherein oscillation frequency of the lens is about 10 to about 50 Hz;
sensing a focus error signal generated in response to the oscillation of the lens;
determining distances from a reference location to the oscillating lens from a predetermined characteristic of the focus error signal; and
determining a relationship between the oscillating signal and the determined distances from the reference location to the oscillating lens.
12. An optical disc drive comprising:
means for generating an oscillating input signal;
means for oscillating a lens in time at an oscillation frequency in response to the oscillating input signal, wherein the oscillation frequency is about 10 to about 50 Hz;
means for generating a focus error signal in response to the oscillation of the lens;
means for determining distances from a reference location to the oscillating lens from a predetermined characteristic of the focus error signal; and
means for determining a relationship between the oscillating input signal and the determined distances from the references location to the oscillating lens.
28. A computer-usable medium containing computer-readable instructions for causing an optical disc drive to perform a method comprising:
inputting an oscillating signal into an actuator, causing the actuator to oscillate a lens, wherein oscillation frequency of the lens is about 10 to about 50 Hz;
sensing a focus error signal generated in response to the oscillation of the lens;
determining distances from a reference location to the oscillating lens from a predetermined characteristic of the focus error signal; and
determining a relationship between the oscillating signal and the determined distances from the reference location to the oscillating lens.
15. An optical disc drive comprising:
a lens actuator;
a lens connected to the lens actuator; and
a controller electrically coupled to the lens actuator, the controller adapted to cause the optical disc drive to
input an oscillating input signal to the actuator, causing the actuator to oscillate at an oscillation frequency,
wherein the oscillation frequency is about 10 to about 50 Hz;
sense a focus error signal generated in response to the oscillation of the lens;
determine a distances from a reference location to the oscillating lens from a predetermined characteristic of the focus error signal; and
determine a relationship between the oscillating input signal and the determined distances from the references location to the oscillating lens.
8. A method of operating a disc drive, comprising:
applying an oscillating signal to an actuator that causes the actuator to oscillate a lens, wherein the oscillation frequency of the lens is about 10 to about 50 Hz;
outputting an oscillating voltage from an astigmatic photo sensor in response to passing light from a light source through the oscillating lens and onto the astigmatic photo sensor after reflecting it from a surface of an optical disc;
determining distances from a focus point of the lens to the lens from the oscillating output voltage and a relationship determined for a focus error signal output by the astigmatic photo sensor; and
determining a relationship between the oscillating signal applied to the actuator and the distances from the focus point of the lens to the oscillating lens.
24. An optical disc drive comprising:
an input signal source;
a lens actuator electrically coupled to the input signal source;
a lens connected to the lens actuator;
a light source;
an astigmatic photo sensor optically coupleable to an optical disc, the photo sensor adapted to generate a focus error signal for the lens in response to receiving light, from the light source, that passes through the lens and is reflected off the optical disc; and
a controller electrically coupled to the photo sensor and the input signal source, the controller adapted to cause the optical disc drive to perform a method comprising:
sending an oscillating signal to the actuator from the input signal source that causes the actuator to oscillate the lens at an oscillation frequency, wherein the oscillation frequency is about 10 to about 50 Hz;
outputting an oscillating voltage from the photo sensor in response to passing light, from the light source, through the lens and onto the photo sensor after reflecting it off the optical disc;
determining distances from a focus point of the lens to the lens from the oscillating output voltage and a relationship determined for the focus error signal output by the astigmatic photo sensor; and
determining a relationship between the oscillating signal sent to the actuator and the distances from the focus point of the lens to the oscillating lens.
2. The method of
3. The method of
4. The method of
5. The method of
7. The method of
9. The method of
using the determined relationship to set the lens at a position where the lens is defocused; and
forming a label on the surface of the optical disc using light, from the light source, that is passed through the defocused lens.
10. The method of
11. The method of
13. The optical disc drive of
means for setting the lens at a position where the lens is defocused using the determined relationship; and
means for forming a label on a surface of an optical disc using light that is passed through the defocused lens.
14. The optical disc drive of
16. The optical disc drive of
17. The optical disc drive of
18. The optical disc drive of
19. The optical disc drive of
20. The optical disc drive of
21. The optical disc drive of
use the determined relationship to set the lens at a position where the lens is defocused; and
form a label on an optical disc using light that is passed through the defocused lens.
22. The optical disc drive of
23. The optical disc drive of
25. The optical disc drive of
using the determined relationship to set the lens at a position where the lens is defocused; and
forming a label on the optical disc using light, from the light source, that is passed through the defocused lens.
26. The optical disc drive of
27. The optical disc drive of
29. The non-transitory computer-usable medium of
30. The non-transitory computer-usable medium of
31. The non-transitory computer-usable medium of
32. The non-transitory computer-usable medium of
33. The non-transitory computer-usable medium of
34. The non-transitory computer-usable medium of
using the determined relationship to set the lens at a position where the lens is defocused; and
forming a label on the surface of the disc using light from the light source that is passed through the defocused lens.
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Optical discs, such as compact discs (CDs) and digital versatile discs (DVDs), are a form of computer-readable media that provide storage for digital information. Some optical discs may be read-only, while others may also be written to. Typically, one side of an optical disc is referred to as a data side, while the other side is referred to as a label side. The label side may include label text and/or graphics.
An optical disc drive is used to read from and, in some cases, to write to the data side of an optical disc. An optical pickup unit is included in the optical disc drive and is configured with a laser and sensors for reading from and writing to the data side. An optical pickup unit may also be configured for writing to the label side. However, writing to the label side may involve using a larger laser spot size to write on the label side than on the data side because the tracks written to the label side are generally wider than are commonly written on the data side. Therefore, writing to the label side often involves defocusing the laser spot to make it larger. One problem that may occur with this is controlling the defocusing so as to optimally adjust the spot size.
In the following detailed description of the present embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments that may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice disclosed subject matter, and it is to be understood that other embodiments may be utilized and that process, electrical or mechanical changes may be made without departing from the scope of the claimed subject matter. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the claimed subject matter is defined only by the appended claims and equivalents thereof.
Disc media marking device 105 typically includes one or more processors 115 (e.g., any of microprocessors, controllers, and the like) that process various instructions to control the operation of disc media marking device 105 and communicate with other electronic and computing devices. Disc media marking device 105 may be implemented with one or more memory components, examples of which include a random access memory (RAM) 120, a disc storage device 125, and a computer-usable medium, such as nonvolatile memory 130, (e.g., any one or more of a read-only memory (ROM) 135, flash memory, EPROM, EEPROM, etc.).
Disc storage device 125 may include any type of magnetic or optical storage device, such as a hard disc drive, a magnetic tape, a recordable and/or rewriteable compact disc (CD), a DVD, DVD+RW, and the like. The one or more memory components provide data storage mechanisms to store various information and/or data, such as configuration information for disc media marking device 105, graphical user interface information, and any other types of information and data related to operational aspects of disc media marking device 105. Alternative implementations of disc media marking device 105 may include a range of processing and memory capabilities, and may include any number of differing memory components than those shown in
Disc media marking device 105 may include a firmware component 140 that is implemented as a permanent memory module stored on ROM 135, or with other components in disc media marking device 105, such as a component of, a processor 115. Firmware 140 is programmed and distributed with disc media marking device 105 to coordinate operations of the hardware within disc media marking device 105 and contains programming constructs used to perform such operations.
An operating system 145 and one or more application programs may be stored in nonvolatile memory 130 and executed on processor(s) 115 to provide a runtime environment. A runtime environment facilitates extensibility of disc media marking device 105 by allowing various interfaces to be defined that, in turn, allow the application programs to interact with disc media marking device 105. In this example, the application programs include a label design application 150, an image processing application 155, and a print control application 160. Furthermore, it is contemplated that VCM gain measurements 165 are stored in non-volatile memory, such as nonvolatile memory 130. In certain embodiments, VCM gain measurements 165 are stored in non-volatile sections of RAM 130 or ROM 135. VCM gain measurements are inherent to the particular VCM, and specifically related to the metal used in the VCM windings and the number of windings of the VCM and the temperature at which the measurement was made.
The label design application 150 generates a label design user interface 170 for display on display device 110 from which a user may create a label image to be rendered on a disc media, such as on an optical disc. A user may specify text, a bitmap image for background, a digital photo, a graphic or symbol, and/or any combination thereof to create the label image on the user interface 170.
The image processing application 155 processes the label image created with the label design user interface 170 to produce a data stream of label image data and laser control data for labeling the image on concentric circular or spiral tracks of a disc media (i.e., an optical disc). For example, a continuous tone RGB (red, green, and blue) rectangular raster graphic of the label image may be color mapped and separated into the printing color channels KCMY (black, cyan, magenta, and yellow) or grayscale, and then halftoned and converted to tracks. This data stream may be formatted as laser control data and may be augmented with other control commands to control the disc media marking device 105 rendering a label on the disc media.
A label file may be generated using image processing application 155. The label file is communicated to a controller 260 (
The print control application 160 determines the radius from the hub of the disc of the first track, and the subsequent track spacing. After the radius of the first track and the track spacing are determined, the print control application 160 determines which label image data will correspond to each respective track. The laser mark locations along a particular track are specified in a coordinate system where the concentric circular tracks are defined in coordinates of the radial distance and the distance along each respective track.
Disc media marking device 105 includes an optical disc drive (ODD) system 175 that may be configured to produce visible marks on a surface of a disc media (i.e., optical disc), so as to produce a label image on a label region (for example, a label side) of the optical disc. In one embodiment, the label region has an electromagnetic radiation-sensitive coating disposed on the disc. Optically visible marks may be formed at desired locations of the label region by application of laser energy of a specified frequency, power, and duration to the desired locations. One such suitable media is as described in U.S. Patent Application Publication No. 2003/0108708 A1, for example. The ODD system 175 is described in greater detail herein below with reference to
Disc media marking device 105 may further include one or more communication interfaces 180 that may be implemented as any one or more of a serial and/or parallel interface, as a wireless interface, any type of network interface, and as any other type of communication interface. A wireless interface enables disc media marking device 105 to receive control input commands and other information from an input device, such as a remote control device or from other infrared (IR), 802.11, Bluetooth, or similar RF input device. A network interface provides a connection between disc media marking device 105 and a data communication network to send label image data and other information to disc media marking device 105 via the network. Similarly, a serial and/or parallel interface provides a data communication path directly between disc media marking device 105 and another electronic or computing device.
Disc media marking device 105 may include user input devices 185 that may include a keyboard, pointing device, selectable controls on a user control panel, and/or other mechanisms to interact with and to input information to disc media marking device 105. Disc media marking device 105 also includes an audio/video processor 190 that generates display content for display on display device 110 and generates audio content for presentation by a presentation device, such as one or more speakers (not shown). The audio/video processor 190 may include a display controller that processes the display content to display corresponding images on display device 110. A display controller may be implemented as a graphics processor, microcontroller, integrated circuit, and/or similar video-processing component to process the images. Video signals and audio signals may be communicated from disc media marking device 105 to display device 110 via an RF (radio frequency) link, S-video link, composite video link, component video link, or other similar communication link.
Although shown separately, some of the components of disc media marking device 105 may be implemented in an application specific integrated circuit (ASIC). Additionally, a system bus (not shown) typically connects the various components within disc media marking device 105. A system bus may be implemented as one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, or a local bus using any of a variety of bus architectures. Furthermore, disc media marking device 105 may share a system bus with a host processor.
For purposes of illustration, the lens 215 is carried by lens supports 225(1), 225(2). The lens 215 is configured for travel (i.e., adjustment of the focal point) along a z-axis 230 perpendicular to a surface of an optical disc 235. Photo sensor 212 determines a distance along z-axis 230 at which an “in focus” condition of the laser beam exists with respect to a particular location on the surface of optical disc 235. VCM 220 is calibrated to move to this particular distance by receiving a particular input signal.
However, in some embodiments, it may be desirable to further adjust the z-axis position so as to intentionally defocus the laser beam. This intentional defocusing, or “focus offset,” may be provided in order to provide a better image quality using a marking laser. For example, the size of the visible spots created by a focused laser may be too small to allow efficient labeling, so a defocused laser beam may be used to created larger visible spots. Or the marking laser may create such distortion from its heat when marking a surface, as to provide a need for an adjusted focus offset. A predetermined amount of focus offset may be achieved by adjusting the input signal by a corresponding focus offset value.
A laser beam 240 is generated by the laser 210 and directed onto (reflected on) a label side surface 245 of optical disc 235. The laser beam 240 creates visible laser marks that correspond to label image data to produce an image of the label side 245 of the optical disc 235.
The ODD system 175 includes a spindle motor 250, a VCM (or sled motor) 255, and a controller 260. For one embodiment, controller 260 includes an analog-to-digital converter and a digital-to-analog converter. VCM 255 moves OPU assembly 200 adjacent to particular radial positions or tracks of optical disc 235. VCM 255 is calibrated to move to this particular distance by receiving a particular input signal. VCM 255 may be referred to as a sled or radial VCM since it provides movement in the radial direction. VCM 255 may be calibrated for gain, i.e., input signal (e.g., milivolts) per movement (microns), such that, for example, a particular number of milivolts results in a movement of a particular distance.
A separate stepper motor 256 provides a coarse adjustment for radial movement, and particularly is calibrated to move per a step size increment as instructed by controller 260. VCM 255 includes a fine adjust feature 257. While stepper motor 256 is calibrated to move per a step size increment, fine adjust feature 257 is calibrated to adjust to a finer increment. For example, if stepper motor 256 is calibrated for a step size of 120 microns, and fine adjust feature 257 is calibrated for a smaller increment, when 80 microns of movement is requested, stepper motor 256 moves the sled 205 by 120 microns, and fine adjust feature 257 moves the sled 205 back by 40 microns.
In general, controller 260 may be implemented as a printed circuit board employing a combination of various components discussed above with respect to the disc media marking system 100 of
Drivers 269, including a laser driver, sled driver, and spindle driver are stored in memory 266 and executable on processor 263. Although these components are represented in the
In general, a spindle driver drives the spindle motor 250 to control a rotational speed of optical disc 235 via a spindle 272. The spindle driver operates in conjunction with a sled diver that drives the VCM 255 to control radial (track) positioning of OPU assembly 200 with respect to disc 235 along a sled drive mechanism 275. In a labeling implementation, the sled 205 of the OPU assembly 200 is moved along the sled drive mechanism 275 to various radii (track) positions of optical disc 235.
In a labeling implementation, the rotational speed of disc 235 and the radial position of OPU assembly 200 are controlled such that laser marks are written at desired positions on the disc 235 as the label side surface 245 moves past the laser beam 240.
A laser driver controls the activation and intensity of laser beam 240 to write laser marks corresponding to a label image onto the label side surface 245. Additionally, the laser driver controls the activation and intensity of the laser beam 240 to read data maintained on the data side 278 of the optical disc 235 when the disc is positioned such that the data side 278 passes over the laser beam 240. While in some embodiments the data region and the label region are on opposite sides of the disc, in other embodiments the data region and the label region are located on the same side of the disc.
A driver for VCM 220 is included among the drivers 269. The VCM driver is executable on processor 263 to adjust a VCM power amplifier 281 that provides an input to VCM 220. Furthermore, another driver is included for VCM 255 executable on processor 263 to adjust a VCM power amplifier 284 that provides an input to VCM 255. Input signals may be either current or voltage. As discussed, VCMs 220 and 255 may be calibrated at a particular operating temperature, for one embodiment. Therefore, input signals are based on the particular calibrated operating temperature. However, operating the OPU assembly at temperatures other than the calibrated operating temperature may result in different distances for a given input signal from the VCMs 220 and 255.
Computing device interface 296 interfaces the controller 260 of the ODD system 175 with another electronic or computing device to receive label image data or a label file (not shown). The computing device interface 296 can be implemented as an ATAPI (Advanced Technology Attachment Packet Interface) that is one of many small computer parallel or serial device interfaces. Another common computer interface is SCS1 (small computer system interface) that is a generalized device interface for attaching peripheral devices to computers. SCS1 defines the structure of commands the way commands are executed and the way status is processed. Various other physical interfaces include the Parallel Interface, Fiber Channel, IEEE 1394. USB (Universal Serial Bus), and ATNATAPI. ATAP1 is a command execution protocol for use on an ATA interface so that CDROM and tape drives can be connected via the same ATA cable with an ATA hard disc drive. ATAPI devices generally include CDROM drives, CD-recordable drives, CD-rewritable drives, DVD (digital versatile disc) drives, tape drives, super floppy drives (e.g., ZIP and LS1ZO), and the like.
Photo sensor 212 provides laser focus feedback to the laser driver. For one embodiment, photo sensor 212 is an astigmatic sensor and includes four sensor quadrants: quadrants A, B, C, and D, as shown in
Controller 260 uses the focus error signal to determine whether lens 215 is in focus and, when reading to or writing from the data region, to keep lens 215 in focus. At distances closer to optical disc 235 than the distance corresponding to point E, and distances further from optical disc 235 than the distance corresponding to point G, the focus error signal is not valid. Therefore, the substantially linear portion of the focus error signal can be referred to as its useful region. For one embodiment, the distance axis in
The extent of the linear region and the distance from center of the maximum and minimum are functions of the design of the optical path and remain fairly constant for a given drive design. Therefore, the gain value that relates the distance moved by the lens to the voltage of FES in the linear region can be characterized for a drive design and stored in non-volatile memory. This characterization can be done in the factory using a means of measuring the distance moved by the lens and the voltage at FES.
For one embodiment, controller 260 uses the focus error signal to determine whether lens 215 is in focus and to keep lens 215 in focus using a feedback control system, where the focus error signal is fed through a compensator, e.g., located in processor 263, VCM power amplifier 281, and then into VCM 220. For another embodiment, this can be done without feedback if care is taken to reduce mechanical noise that might move VCM 220 outside the linear region of the FES signal.
For one embodiment, an equation of the focus error signal, e.g., in the substantially linear region between points E and G, can be determined by moving lens 215 to a number of locations along the z-axis, recording the corresponding output voltages of photo sensor 212, and fitting a curve, such as a least squares curve, through the voltage versus location (or distance) data. For another embodiment, the raw data or data generated by the equation may be stored in a look-up table, such as look-up table 287 in
For one embodiment, VCM power amplifier 281 adds an offset signal (voltage or current), at block 410, to a feedback control signal coming from the compensator and the sum of these signals is inputted to the VCM 220, and at block, 430, the gain of VCM 220 is determined from the magnitude of the offset signal.
For one embodiment, controller 260 may be programmed to maintain the output of photo sensor 212, e.g., the focus error signal, at a particular set point, such as the point F of
For example, controller 260 can be set to maintain the focus error signal at an offset point, e.g. point a of plot 300, relative to the set point F. A plot, a look-up table, gain, or equation of the focus error signal can be used to determine the distance d between set point F and offset point a, in
Although specific embodiments have been illustrated and described herein it is manifestly intended that the scope of the claimed subject matter be limited only by the following claims and equivalents thereof.
Van Brocklin, Andrew L., Hanks, Darwin M.
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| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| May 25 2005 | VAN BROCKLIN, ANDREW L | HEWLETT-PACKARD DEVELOPMENT COMPANY, L P | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 016778 | /0683 | |
| Jul 12 2005 | Hewlett-Packard Development Company, L.P. | (assignment on the face of the patent) | / | |||
| Jul 12 2005 | HANKS, DARWIN M | HEWLETT-PACKARD DEVELOPMENT COMPANY, L P | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 016778 | /0683 |
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